One reason for a drop in reports of resident species in late Summer is
that many species go into skulk-mode during pre-basic molt. The late JB
Owen always pointed out that August is the one month where it can be
difficult to find and hear a singing Mockingbird.
Dean Edwards
Knoxville, TN
On Mon, 7 Sep 2015, Bill Pulliam wrote:
I meant to respond to this one a while back but evidently did not...=================NOTES TO SUBSCRIBER=====================
EBird filters serve a lot of purposes. One of these is typo checking. For
example, Yellow-throated Warblers occur all summer in Davidson County (filters
only have county-level spatial resolution), but they become much less
conspicuous after late July when singing quiets down. There are ZERO existing
eBird reports of the species from Davidson County in the first three weeks of
August, and it is not reported regularly again until the second week of
September when there is a small autumn influx (of birds or birders?). So in
fact this filter is quite finely calibrated, and an August Yellow-throated
Warbler is flagged as a check that it is being reported deliberately and not
as a typo. With increasing use of the mobile apps, typos are increasing as
well...
There are many small-scale seasonal variations in the apparent abundances of
birds that are obvious in eBird data but which are often surprising and poorly
recognized amongst most birders. A few examples from Davidson County are:
--Woodpeckers of all species show a sharp drop in reported numbers in the
summer
--Many summer resident woodland passerines that are known mostly by their
voices become quite infrequently detected in late summer and early fall, to
the point that they may appear to vanish entirely from the data. This is not
just a function of reduced birder activity, as these frequency and abundance
numbers are adjusted for effort.
--Red-winged Blackbirds and Eastern Meadowlarks drop drastically in early
September, only to reappear magically by the end of the month.
--House Sparrows become unaccountably scarce in September and October - where
do they go?
Many of these patterns are incorporated in the eBird filters, not because
these birds are actually "rare" at these season. Rather, it is because they
are --> infrequently reported <-- at these seasons, so it is worth the double
check to make sure that you tapped out the right 4-letter code or typed the
correct number into the correct box on the checklist form. Typos among common
species can be very difficult errors to catch after they get into the
database, so every safeguard that might intercept them before they get there
helps. If you want a guide as to which species are actually expected in an
area your best guide is the eBird bar graph for the area, not the eBird
screening filter.
Bill Pulliam
Hohenwald TN
From: Chris Sloan <csloan1973@xxxxxxxxx>
Date: Mon, 24 Aug 2015 11:30:38 -0500
Subject: [TN-Bird] Re: Radnor Lake, Davidson County, 8-22-15
They breed at Radnor Lake. Some of the eBird filters are still not finely
calibrated.
Chris Sloan
Nashville, TN
http://www.chrissloanphotography.com
On Mon, Aug 24, 2015 at 11:28 AM, Graham <grahamgerdeman@xxxxxxxxx> wrote:
Davidson County
August 22, 2015
I spent a couple of hours on a whim out at Radnor on Saturday. Great looks
at Belted Kingfisher fishing and young Eastern Kingbirds, etc. and the
usual cast of characters.
Also a beautiful male Yellow-Throated Warbler gleaning on a sycamore right
near the valve house trail / spillway. I didn't think this was an unusual
sighting, but it was questioned on ebird, so I figured I might report it
here as well. I didn't bother with a photo because it was a bit out of
range to get a "keeper," but the bird was unmistakably a YTWA. Early
migrant? I thought these birds were local breeders, but I may be putting
too much stock in range maps.
Graham Gerdeman
Nashville
=================NOTES TO SUBSCRIBER=====================
The TN-Bird Net requires you to SIGN YOUR MESSAGE with
first and last name, CITY (TOWN) and state abbreviation.
You are also required to list the COUNTY in which the birds
you report were seen. The actual DATE OF OBSERVATION should
appear in the first paragraph.
_____________________________________________________________
To post to this mailing list, simply send email to:
tn-bird@xxxxxxxxxxxxx.
_____________________________________________________________ To
unsubscribe, send email to:
tn-bird-request@xxxxxxxxxxxxx with 'unsubscribe' in
the Subject field.
______________________________________________________________
TN-Bird Net is owned by the Tennessee Ornithological Society Neither the
society(TOS) nor its moderator(s)
endorse the views or opinions expressed
by the members of this discussion group.
Moderator: Wallace Coffey, Bristol, TN
wallace@xxxxxxxxxxxxxxxxxxx
------------------------------
Assistant Moderator Andy Jones
Cleveland, OH
-------------------------------
Assistant Moderator Dave Worley
Rosedale, VA
--------------------------------
Assistant Moderator Chris O'Bryan
Clemson, SC
__________________________________________________________
Visit the Tennessee Ornithological Society
web site at http://www.tnbirds.org
* * * * * * * * * * * * * * * * * * * * * * * * * * * * *
ARCHIVES
TN-Bird Net Archives at //www.freelists.org/archives/tn-bird/
MAP RESOURCES
Tenn.Counties Map at http://www.lib.utexas.edu/maps/states/tennessee3.gif
Aerial photos to complement google maps http://local.live.com
_____________________________________________________________
